A new beetle that vectors a Fusarium dieback on avocado trees has been discovered in and near Los Angeles County. The newly discovered polyphagous shot hole borer beetle is indistinguishable from the tea shot hole borer beetle and is believed to be a new species of beetle.

Healthy avocado roots play an important role in producing consistent high-quality avocado crops from healthy avocado trees. Roots provide nutrients and water for strong healthy leaves, good shoot growth, flowering and fruit set, and avocado fruit growth.

Phytophthora mengei (P. citricola) and P. cinnamomi have been associated with trunk canker and collar rot of avocado. The pathogen infects the crown, lower trunk and limbs of older trees. The disease develops after crowns, limbs, or trunks become infected through wounds, such as injuries from equipment, pruning, vertebrate chewing, and wind damage.

The measures recommended for the control of Phytophthora avocado trunk canker disease are similar to those described for Phytophthora root rot. In fruit, prevention of infection is challenging because it is likely caused by the splashing of Phytophthora spores from the soil surface to the fruit during rainy weather.